1. Field of the Invention
The present invention relates to a data recording apparatus that captures data to be continuously processed such as video data or voice data into a computer, converts the data to a file and records it in a recording medium such as a hard disk.
2. Related Art of the Invention
Capturing video data recorded in a video camera, etc. into a computer and converting it in an animation file is called “image capturing.” A typical example of formatting of this image captured animation file is an AVI file handled by the Windows operating system.
With commercialization of the IEEE1394 interface and increasing-capacity of hard disk drives in recent years, it is now possible to handle relatively low-compression rate video data such as DV (Digital Video) as an AVI file.
As a result, it is possible to easily capture a high-quality animation recorded in a DV format into a computer and to edit it by software without deterioration of image quality.
However, handling an AVI file involves the following problems:
(1) The maximum capacity of one file handled by Windows is 2^31 bytes (“^” denotes power), that is, 2 GB. On the contrary, video data in a DV format which is suitable for NTSC format of present TV signal is 120,000 bytes per 1 frame and so when DV data is captured, only data for approximately 9 minutes can be captured even if there is an enough space in the hard disk. Thus, a problem arises that if one file becomes full, subsequent image data must be abandoned. Furthermore, even if the data spilling out of the file is stored in another file, when it is stored in the other file in the middle of a frame, that is, one frame is recorded on different areas noise can occur in the reproduced data.
(2) Furthermore, an animation or voice mode in an AVI file format must be unique within one file. For example, mode information that indicates a voice mode includes a sampling frequency and the sampling frequency must be constant in one AVI file.
On the contrary, it is known that in a DV format, three types of voice sampling frequency of 48 kHz, 44.1 kHz and 32 kHz are mixed within one file and a mixture of these three may exist on one tape. Therefore, if such animation is captured in a conventional AVI file format, a problem arises that that when reproduced, the stored data may include noise.
(3) Furthermore, since animation and voice data converted to an AVI file are digital data, the copyright issue should be taken into account. Generally, an AVI file contains copyright information that means the file (1) can be reproduced any number of times (COPY FREE), (2) can be reproduced only one time (COPY FREE) or (3) cannot be reproduced (COPY NEVER or COPY NO MORE). Capturing or reproducing animation ignoring this copyright information is not permitted. However, when data is converted to an AVI file conventionally, a problem arises that copyright is not taken into account enough.
(4) Furthermore, when the remaining recording capacity of a recording area (normally partition) becomes 0 during capturing, a problem arises that that no more video data can be recorded. Even if the remaining data is recorded in another recording area, when the recording area is switched in the middle of a frame, that is, one frame is recorded on different areas, a problem arises that that noise can be generated when the data is reproduced.